In the past, resistance apparatus of varying types have been developed. Thus, apparatus has been developed to facilitate training in various sports, such as in tennis, or hitting a baseball, and one such device is shown in U.S. Pat. No. 2,134,451. This device includes first and second pulley blocks, the first pulley block being mounted on a wall, a rope, cable or the like (herein after referred to as a line), the line having an intermediate portion which passes over the sheave in the first pulley block and which has one end secured to the first block, another intermediate portion of the line engaging the sheave on the second pulley block, which second pulley block carries a weight. A baseball bat or tennis racket may be secured to the free end of the line, and the swinging of the bat or racket is resisted by the weight carried by the second pulley block. This device has the disadvantages in that it must be more or less permanently secured to the wall, and it only has limited applications.
U.S. Pat. No. 4,109,907 disclosed a home exercise device which includes clip means for removable engagement over the upper edge of a door, which clip means supports pulley blocks to which weights and resistive training devices may be secured. While this device may be useful for its intended purposes, it lacks versatility and requires that a door be utilized.
It has been suggested that a resistance weight training device may be secured within a door frame and this is shown in U.S. Pat. Nos. 4,243,219 and 4,344,618. Neither one of these patents discloses a device which may be readily carried from one location to another. U.S. Pat. No. 4,619,453 also discloses a door frame resistance training device, but this device is unduly complicated.
U.S. Pat. No. 4,290,598 discloses a resistance or tension exerciser which may be supported from the joists of a ceiling.
Other apparatus has been developed for use in rehabilitation of injuries and for physical therapy. However, most rehabilitative apparatus is either very specialized, expensive, or both.